President Donald Trump, who will be nominating Kennedy's replacement, has vowed to appoint pro-life judges.

Other experts say that while Kennedy's replacement is likely to be conservative, Roe v. Wade is unlikely to be overturned.

CNN legal analyst Jeffrey Toobin predicted on Wednesday that Supreme Court Justice Anthony Kennedy announcing his retirement and vacating a spot for President Donald Trump to fill meant Roe v. Wade, the landmark case establishing the right to abortion access, was "doomed."

"Let's talk about facts. Let's talk about what America is like that is going to be different. You are going to see 20 states banning abortion outright," Toobin said. "Because they know that there are going to be five seats on the Supreme Court to overturn Roe v. Wade."

Trump and a Republican-controlled Senate will now nominate and confirm a justice to fill the seat vacated by Kennedy, and it has abortion-rights advocates all over the country concerned.

During his presidential campaign, Trump vowed to nominate pro-life justices to the federal courts who supported overturning Roe v. Wade. Meanwhile, individual states all over the country have been testing the limits of Roe v. Wade and a subsequent case, Casey v. Planned Parenthood, in which the Supreme Court ruled that states cannot place an "undue burden" on patients seeking abortion.

States have enacted legislation that chips away at abortion access in a strategy experts call "death by a thousand cuts." These have included bills that ban abortion after a certain number of weeks, require patients to go through a waiting period or listen to their fetus's heartbeat, or enact restrictions on abortion clinics that have forced many to shut down.

Reproductive rights advocates fear that a Supreme Court with five conservative justices will be more likely to uphold such laws if they come before the court.

"The significance of today's news cannot be overstated: The right to access abortion in this country is on the line," Planned Parenthood Executive Vice President Dawn Laguens said in a statement to Business Insider. "The idea of Trump having his choice to fill another vacancy is terrifying for not only abortion rights, but for our ability to live free from discrimination in this country."

Legal experts, however, say that while Kennedy's replacement will probably be conservative on abortion, the chances of Roe v. Wade being fully overruled are slim.

"In part because of electoral politics and the need to turn out the Republican base, it is likely the President will very publicly focus on abortion issues in vetting his next nomination. It is probable that Kennedy's successor will be more anti-choice than Kennedy was," Glenn Cohen, a Professor at Harvard Law School and an expert on medical ethics, told Business Insider.

"That said, I do not think it particularly likely that Roe (and Casey) are likely to be overturned based on this one appointment," Cohen added. "I find it hard to think that [Chief Justice] Roberts — who has a more long-term view of the arc of the court and a desire to preserve its institutional role — would facially overrule Roe."

Kenneth Cuccinelli, a former Virginia attorney general who appeared alongside Toobin on CNN to discuss Kennedy's retirement, slightly disagreed with the scope of Toobin's assessment, but acknowledged it had a grain of truth.

"Not 20 states. There will be some states, but they will be in a very distinct minority," he said.